Hyperfine induced 2s2pP03→2s2S01 transition rates in an external magnetic field for Be-like 47Ti were calculated based on the multiconfiguration Dirac-Fock method. It was found that the transition probability is dependent on the magnetic quantum number M of the excited state, even in the weak field. The present investigation clarifies that the difference of the hyperfine induced transition rate of Be-like Ti ions between experiment [Schippers, et al., Phys. Rev. Lett. 98 (2007) 033001(4)] and theory does not result from the influence of external magnetic field.